Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to automatic rewind detection of magnetic tape cassettes such as videocassettes, and more particularly to electromagnetic detection of a winding of magnetic tape within a magnetic tape cassette to determine if the magnetic tape is in a rewound position.
2. Description of the Related Art
Presently, in the videotape rental business it is customary that rented videocassettes are to be rewound prior to returning. Many videotape rental stores charge a rewind fee for videocassettes that are returned but not rewound. Videocassettes are typically rented in individual protective containers. Store personnel must visually inspect each videocassette to determine if the returned videocassette has been rewound, and typically must open each individual videocassette container to view the videocassette contained therein. If rewound, the videocassette can be returned to appropriate storage and display shelves. If the returned videocassette has not been rewound, the store personnel rewinds the videocassette and charges the customer a fee for this service. However, requiring visual inspection of each returned videocassette is time consuming, and may not always be performed by store personnel, especially during busy hours at the videotape rental store. Consequently, there is a need for an automatic method of determining if returned videocassettes have been rewound.
With the advent of radio frequency identification (RFID), self-service check-in and checkout of videocassettes is possible. Self-checkout/check-in can speedup the process of renting and returning videotapes by reducing the required interaction of store personnel. If a videotape is returned via self-check-in, a requirement that store personnel must visually inspect every returned videocassette to determine the rewind status defeats some of the advantages of self-check-in. Clearly, in a self-check-in environment there is an even greater need for automatic determination of the rewind status of a returned videocassette.
The present invention is an apparatus and method for determining the position of magnetic tape within a magnetic tape cassette to ascertain whether the magnetic tape is in a rewound position within the cassette. In a first aspect of the present invention, the magnetic tape cassette has two internal magnetic tape take-up reels. The magnetic tape stored on the tape-up reels is detected. The rewound status of the tape is determined by whether the magnetic tape is detected on only one reel or on both reels. The magnetic tape can be detected using an LC resonant circuit or an inductive balanced bridge circuit.
In a second aspect of the present invention, a preselected amount of magnetic tape is detected within the magnetic tape cassette. The magnetic tape cassette is oriented and the position of the detected magnetic tape is determined relative to the orientation of the magnetic tape cassette. The magnetic tape can be detected within an aperture in a housing using an LC resonant circuit or an inductive balanced bridge circuit. The orientation of the magnetic tape cassette is determined by physically or mechanically positioning the cassette, or by detecting an electronically detectable member positioned on or in a known location of the cassette. The time difference between the detection of the magnetic tape and the detection of the electronically detectable member can be used to determine the position of the magnetic tape relative to the cassette. The electronically detectable member can be detected within the aperture using an LC resonant circuit, an inductive balanced bridge circuit, or a harmonic detector. The electronically detectable member can be an electronic article surveillance marker. Alternately, the leading edge of the cassette can be detected upon entry into the aperture, and the time difference between the detection of the magnetic tape and the detection of the leading edge of the cassette can be used to determine the position of the magnetic tape relative to the cassette. Detection of the leading edge of the cassette can be by photo sensor.
In a third aspect of the present invention, an electronically detectable member positioned in a known location of the cassette is detected. A preselected amount of magnetic tape within the cassette is detected. The time difference between the detection of the magnetic tape and the detection of the electronically detectable member is used to determine the position of the magnetic tape relative to the cassette. The electronically detectable member can be an electronic article surveillance marker. The marker can be detected using an LC resonant circuit or an inductive balanced bridge circuit. The preselected amount of magnetic tape can be detected using an LC resonant circuit or an inductive balanced bridge circuit.
A fourth aspect of the present invention provides a method for determining the position of magnetic tape within a magnetic tape cassette having two magnetic tape take-up reels by first detecting magnetic tape within the cassette. The position of the magnetic tape is then determined as a function of whether the magnetic tape is detected on one or both of the take-up reels.
A fifth aspect of the present invention provides a method for determining the position of magnetic tape within a magnetic tape cassette by first orienting the cassette. Then a preselected amount of magnetic tape within the cassette is detected, and the position of the preselected amount of magnetic tape is determined as a function of the orientation of the cassette. Orienting the cassette can be done physically or mechanically, or by detecting an electronically detectable member positioned in a known location on or in the cassette. The time difference between detecting the electronically detectable member and detecting the preselected amount of magnetic tape is then determined. The position within the cassette of the preselected amount of magnetic tape is a function of the time difference. Orienting the cassette can be done mechanically or physically by inserting the cassette into an aperture within a housing in a known orientation, or which receives the cassette only in a known orientation. The leading edge of the cassette can then be detected, and the time difference between detecting the leading edge and detecting the preselected amount of magnetic tape is determined. The position within the cassette of the preselected amount of magnetic tape is a function of the time difference.
Accordingly, it is an object of the present invention to determine the position of magnetic tape within a magnetic tape cassette by detecting whether the magnetic tape is on one or both take-up reels within the cassette.
It is a further object of the present invention to determine the position of magnetic tape within a magnetic tape cassette by orienting a magnetic tape cassette and detecting the magnetic tape relative to the known orientation of the cassette.
It is yet another object of the present invention to determine the position of magnetic tape within a magnetic tape cassette by determining the time difference between detecting an electronically detectable member in a known location in or on the cassette, and detecting a preselected amount of magnetic tape within the cassette, where the position of the preselected amount of magnetic tape is a function of the time difference.